Liquid foodstuffs of the milk, juice etc. types are packed and conveyed at present in most cases in finished consumer packages of a non-returnable character which are made from a laminated packing material that customarily consists of thermo-plastic-coated paper. A very large group of these so-called non-returnable packages is manufactured either from prefabricated blanks, from tubular, flattened container cases or from a web of packing material with the help of modern high-capacity packing machines of the type which form, fill and close in a liquid-tight manner the finished packages. A packing machine of the type which manufactures packages from prefabricated tubular container cases is described extensively in, for example, Swedish patent No. 361,857. In order to simplify the present description with respect of the details of the packing machine known already, reference is made to the Swedish patent for closer details concerning the design of the machine. To facilitate an understanding of the present invention however, a summary outline of the manner in which the machine manufactures the packages is provided hereinafter. The flattened container cases, whilst being raised to open tubular shapes, are fed from a magazine positioned close to the machine onto a movable conveyor band which transports the cases into a bottom-forming station at the input end of the machine.
The bottom-forming station comprises one or more intermittently rotatable wheels with radial mandrels whereon the cases supplied are threaded up and transported through a number of forming and sealing stations located round the wheel in order to provide the cases with a liquid-tight bottom closure. From the mandrel-wheel the cases provided with bottoms are placed onto a synchronously driven chain or band conveyor on which the cases in turn and sucession are conveyed to a filling station where the cases are filled with the intended contents. The cases are then conveyed to a top-forming station where the filled cases are provided with a liquid-tight top closure by means of an appropriate forming and sealing operation. After the passage through the top-forming station the finished packages are discharged towards the discharge end of the machine for further distribution.
For optimum utilization of the production capacity of the machine it is customary to operate machines of this type continuously every day of the week from early in the morning until late in the evening with stoppages only at night-time and during planned, regularly recurring periods for more extensive maintenance and service work. Machine stoppages naturally also occur when during normal working hours the machine is to be changed from the filling of one product to another.
The demands on hygiene and cleanliness when handling foodstuffs naturally have to be set very high so that it is possible for the foodstuffs to be stored without any risk of being destroyed or impaired during at least a certain guaranteed keeping period, and also so as to avoid or, minimize for as long as possible, the risk of the foodstuff coming into contact with, or being contaminated by, harmful bacteria and similar microorganisms which could grow rapidly in the foodstuff and and thus become a serious source of the spreading of infections. To meet these demands on cleanliness it is necessary, therefore, that the packing machine be subjected regularly to a cleaning and washing treatment which not only concerns the machine components which during the manufacture of the package come into contact with the contents but also the machine components which run the risk of coming into contact with the contents or which are located in the close surroundings of the production line. Such a thorough cleaning and washing treatment of the machine was carried out up to now more or less manually and was not only time-consuming but was also associated with difficulties with respect to being able to reach and to clean the nooks and corners in the machine which are present in large numbers in such complicated machine designs. In order to avoid unnecessarily disturbing the production of packages, the cleaning work in general was arranged, therefore, to be carried out in periods when the machine is normally out of operation, for example in connection with a machine shutdown for night stoppage. Cleaning work naturally is carried out also in connection with a maching being changed from one product to another.